Here I've shown a 4 foot by 8 foot and 18inch high PVC raised bed and the cost was free. How? For us maybe easier since hog barns are dropping like flies due to the lack of a local kill plant and the market price. We saw a farmer dismantling his operation and he was throwing away the PVC penning. We asked if we could have them.....his response, "fill your boots!" So ask around to find some for yourself.
So we loaded them put on a truck, put them in a field to air out....since pigs barns tend to have an odor, we waited a fews days. Then between free wood pallets and free PVC pig penning we created our 4 foot by 8 foot raised garden beds. Hope this idea gives you some ideas on reusing and recycle materials to use in your garden.